C# Console.WriteLine和通用列表
我经常发现自己在编写这样的代码:C# Console.WriteLine和通用列表,c#,generics,console,list,C#,Generics,Console,List,我经常发现自己在编写这样的代码: List<int> list = new List<int> { 1, 3, 5 }; foreach (int i in list) { Console.Write("{0}\t", i.ToString()); } Console.WriteLine(); List<int> list = new List<int> { 1, 3, 5 }; Console.WriteLine("{0}\t", li
List<int> list = new List<int> { 1, 3, 5 };
foreach (int i in list) {
Console.Write("{0}\t", i.ToString()); }
Console.WriteLine();
List<int> list = new List<int> { 1, 3, 5 };
Console.WriteLine("{0}\t", list);
public static void WriteToConsole<T>(this IList<T> collection)
{
WriteToConsole<T>(collection, "\t");
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
int count = collection.Count();
for(int i = 0; i < count; ++i)
{
Console.Write("{0}{1}", collection[i].ToString(), delimiter);
}
Console.WriteLine();
}
List List=新列表{1,3,5};
foreach(列表中的int i){
Write(“{0}\t”,i.ToString());}
Console.WriteLine();
最好是这样:
List<int> list = new List<int> { 1, 3, 5 };
foreach (int i in list) {
Console.Write("{0}\t", i.ToString()); }
Console.WriteLine();
List<int> list = new List<int> { 1, 3, 5 };
Console.WriteLine("{0}\t", list);
public static void WriteToConsole<T>(this IList<T> collection)
{
WriteToConsole<T>(collection, "\t");
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
int count = collection.Count();
for(int i = 0; i < count; ++i)
{
Console.Write("{0}{1}", collection[i].ToString(), delimiter);
}
Console.WriteLine();
}
List List=新列表{1,3,5};
WriteLine(“{0}\t”,列表);
我怀疑有什么聪明的方法可以做到这一点,但我看不出来。有人有比第一个街区更好的解决方案吗 这样做:
list.ForEach(i => Console.Write("{0}\t", i));
编辑:对已响应的其他人-他希望他们都在同一行上,并且在他们之间有选项卡。:)
List a=newlist(){1,2,3,4,5};
a、 ForEach(p=>Console.WriteLine(p));
编辑:啊,他赢了我。List List=新列表{1,3,5};
list.ForEach(x=>Console.WriteLine(x));
list.ForEach(x=>Console.WriteLine(x));
编辑:该死!打开visual studio进行测试花费的时间太长。另一种方法,只是为了好玩:
Console.WriteLine(string.Join("\t", list));
新列表{1,3,5}.ForEach(Console.WriteLine);
如果有一段代码是你一直在重复的,请不要重复你自己,你应该把它放在你自己的库中并调用它。考虑到这一点,这里有两个方面可以得到正确的答案。首先是调用库函数的代码清晰简洁。第二个是foreach的性能影响
首先,让我们考虑一下调用代码的清晰性和简洁性
您可以通过多种方式执行foreach:
list.ForEach(i => Console.Write("{0}\t", i));
因此,在这个阶段,它可能看起来像列表。ForEach是一条路要走。然而,这部电影的表现如何?的确,在这种情况下,写入控制台的时间将控制代码的性能。当我们了解某一特定语言特征的表现时,我们至少应该考虑一下。
根据优化代码,迭代列表的最快方法是使用for循环,而不调用list.Count
然而,for循环是一个冗长的构造。它还被视为一种非常迭代的方式,与当前功能性习惯用法的趋势不符
那么我们能做到简洁、清晰和性能吗?我们可以使用一种扩展方法。在理想情况下,我们将在控制台上创建一个扩展方法,该方法接受一个列表并使用分隔符写入。我们不能这样做,因为Console是一个静态类,扩展方法只在类的实例上工作。相反,我们需要将扩展方法放在列表本身上(根据David B的建议):
除非我们对扩展方法进行进一步改进,并添加FastForEach,如下所示:
public static void FastForEach<T>(this IList<T> collection, Action<T> actionToPerform)
{
int count = collection.Count();
for (int i = 0; i < count; ++i)
{
actionToPerform(collection[i]);
}
Console.WriteLine();
}
publicstaticvoidfastforeach(此IList集合,Action-actionToPerform)
{
int count=collection.count();
对于(int i=0;i
这允许我们使用最快的迭代方法对集合中的每个元素执行任意代码。
我们甚至可以将WriteToConsole函数更改为使用FastForEach
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
collection.FastForEach(item => Console.Write("{0}{1}", item.ToString(), delimiter));
}
公共静态void writeConsole(此IList集合,字符串分隔符)
{
FastForEach(item=>Console.Write(“{0}{1}”,item.ToString(),delimiter));
}
现在,包括FastForEach示例用法在内的全部源代码如下:
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleWritelineTest
{
public static class Extensions
{
public static void WriteToConsole<T>(this IList<T> collection)
{
WriteToConsole<T>(collection, "\t");
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
collection.FastForEach(item => Console.Write("{0}{1}", item.ToString(), delimiter));
}
public static void FastForEach<T>(this IList<T> collection, Action<T> actionToPerform)
{
int count = collection.Count();
for (int i = 0; i < count; ++i)
{
actionToPerform(collection[i]);
}
Console.WriteLine();
}
}
internal class Foo
{
override public string ToString()
{
return "FooClass";
}
}
internal class Program
{
static void Main(string[] args)
{
var myIntList = new List<int> {1, 2, 3, 4, 5};
var myDoubleList = new List<double> {1.1, 2.2, 3.3, 4.4};
var myDoubleArray = new Double[] {12.3, 12.4, 12.5, 12.6};
var myFooList = new List<Foo> {new Foo(), new Foo(), new Foo()};
// Using the standard delimiter /t
myIntList.WriteToConsole();
myDoubleList.WriteToConsole();
myDoubleArray.WriteToConsole();
myFooList.WriteToConsole();
// Using our own delimiter ~
myIntList.WriteToConsole("~");
// What if we want to write them to separate lines?
myIntList.FastForEach(item => Console.WriteLine(item.ToString()));
Console.Read();
}
}
}
使用系统;
使用System.Collections.Generic;
使用System.Linq;
命名空间控制台WriteLineTest
{
公共静态类扩展
{
公共静态void writeConsole(此IList集合)
{
WriteToConsole(集合“\t”);
}
公共静态void writeConsole(此IList集合,字符串分隔符)
{
FastForEach(item=>Console.Write(“{0}{1}”,item.ToString(),delimiter));
}
公共静态void FastForEach(此IList集合,Action-actionToPerform)
{
int count=collection.count();
对于(int i=0;iConsole.WriteLine(item.ToString());
Console.Read();
}
}
}
您还可以加入:
var qwe = new List<int> {5, 2, 3, 8};
Console.WriteLine(string.Join("\t", qwe));
var qwe=新列表{5,2,3,8};
Console.WriteLine(string.Join(“\t”,qwe));
您必须相对年轻-谁需要Visual Studio?我脑子里一直在想CLR。这是一个非常好的答案!虽然我不喜欢在泛型列表中使用像WriteToConsole
这样的扩展方法。这显然违反了单一责任模式。我不希望列表对控制台有任何了解,无论是在它的实现中还是在扩展方法中。是的,我想您的选择取决于您喜欢什么,以及哪个关注点更大……它不适合您
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleWritelineTest
{
public static class Extensions
{
public static void WriteToConsole<T>(this IList<T> collection)
{
WriteToConsole<T>(collection, "\t");
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
int count = collection.Count();
for(int i = 0; i < count; ++i)
{
Console.Write("{0}{1}", collection[i].ToString(), delimiter);
}
Console.WriteLine();
}
}
internal class Foo
{
override public string ToString()
{
return "FooClass";
}
}
internal class Program
{
static void Main(string[] args)
{
var myIntList = new List<int> {1, 2, 3, 4, 5};
var myDoubleList = new List<double> {1.1, 2.2, 3.3, 4.4};
var myDoubleArray = new Double[] {12.3, 12.4, 12.5, 12.6};
var myFooList = new List<Foo> {new Foo(), new Foo(), new Foo()};
// Using the standard delimiter /t
myIntList.WriteToConsole();
myDoubleList.WriteToConsole();
myDoubleArray.WriteToConsole();
myFooList.WriteToConsole();
// Using our own delimiter ~
myIntList.WriteToConsole("~");
Console.Read();
}
}
}
list.ForEach(i => Console.Write("{0}\t", i));
public static void FastForEach<T>(this IList<T> collection, Action<T> actionToPerform)
{
int count = collection.Count();
for (int i = 0; i < count; ++i)
{
actionToPerform(collection[i]);
}
Console.WriteLine();
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
collection.FastForEach(item => Console.Write("{0}{1}", item.ToString(), delimiter));
}
using System;
using System.Collections.Generic;
using System.Linq;
namespace ConsoleWritelineTest
{
public static class Extensions
{
public static void WriteToConsole<T>(this IList<T> collection)
{
WriteToConsole<T>(collection, "\t");
}
public static void WriteToConsole<T>(this IList<T> collection, string delimiter)
{
collection.FastForEach(item => Console.Write("{0}{1}", item.ToString(), delimiter));
}
public static void FastForEach<T>(this IList<T> collection, Action<T> actionToPerform)
{
int count = collection.Count();
for (int i = 0; i < count; ++i)
{
actionToPerform(collection[i]);
}
Console.WriteLine();
}
}
internal class Foo
{
override public string ToString()
{
return "FooClass";
}
}
internal class Program
{
static void Main(string[] args)
{
var myIntList = new List<int> {1, 2, 3, 4, 5};
var myDoubleList = new List<double> {1.1, 2.2, 3.3, 4.4};
var myDoubleArray = new Double[] {12.3, 12.4, 12.5, 12.6};
var myFooList = new List<Foo> {new Foo(), new Foo(), new Foo()};
// Using the standard delimiter /t
myIntList.WriteToConsole();
myDoubleList.WriteToConsole();
myDoubleArray.WriteToConsole();
myFooList.WriteToConsole();
// Using our own delimiter ~
myIntList.WriteToConsole("~");
// What if we want to write them to separate lines?
myIntList.FastForEach(item => Console.WriteLine(item.ToString()));
Console.Read();
}
}
}
var qwe = new List<int> {5, 2, 3, 8};
Console.WriteLine(string.Join("\t", qwe));